Even so, the ideas that already have been blessed by groups on the left could allow President Barack Obama to get the discussion on entitlements going without infuriating his base.

Here are the highlights of the Democratic entitlement reform menu:

Social Security: 'Chained CPI'

Savings: $112 billion

The idea is to change the way the government figures out how much more seniors should get in Social Security benefits each year to account for changes in their cost of living.

This new formula — a tweak to the consumer price index — would assume that people switch their buying habits when prices rise, rather than just buying the same things over and over. So, for example, if the price of ground beef goes up, someone might buy chicken or fish instead.

The result: Social Security benefits will rise more slowly.

Obama has offered the change before — he supported it during his fiscal cliff talks with Republicans in December. And two think tanks that supply ideas to the Democrats — the liberal Center for American Progress and the more centrist Third Way — have included it in their Social Security plans, giving Obama plenty of cover in case he decides to go that way again.

But a lot of Democrats and liberals aren’t on board. They say seniors are already having a hard enough time with the current cost-of-living increases without dialing them back.

That’s why liberals want any chained CPI agreement to be balanced out with measures to ease the burden on the seniors with the lowest incomes. For example, Paul Van de Water, a senior fellow at the liberal Center on Budget and Policy Priorities, suggests exempting people on Supplemental Security Income — which pays benefits to the lowest-income seniors — and making a special payment to seniors who have been on Social Security for 20 years because they get poorer as they get older.